This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Preschool children with frequent recurrent and intermittent wheezing episodes requiring systemic corticosteroids or ER visits/hospitalizations are a major public health challenge. This group of younger asthmatic children has two major deleterious characteristics compared to older asthmatic children: (1) they suffer greater risk of increased health care utilization and mortality and (2) they experience less favorable responses to asthma management strategies. The National Asthma Education and Prevention Program (NAEPP) and Global Initiative for Asthma require more clinical evidence to define optimal treatment options for these children to reduce acute episodes and impairment related to symptom burden. NAEPP guidelines emphasize two major domains of asthma control: risk and impairment. Risk addresses exacerbation frequency/severity, loss of lung function, and medication side effects. Impairment/burden refers to symptoms, school/work absences, exercise problems, nocturnal awakenings, and current pulmonary function. This study involves 250 well-characterized high-risk API positive children age 12-53 months, with a history of a severe exacerbation in the prior year. Study questions are: 1. Is maintenance low-dose ICS more effective than intermittent high-dose ICS administered during RTI on modifying the risk (rate of an exacerbation requiring systemic corticosteroids is the primary outcome) and impairment domains of recurrent asthma? 2. Are there demographic or asthma/atopic features or CD14-159 genotypes and other genotypes related to ICS responsiveness? 3. Are there are differences in treatment associated adverse effects with these two ICS regimens? 4. Which viruses are associated with exacerbations and which, if any, ICS regimen is better able to ameliorate these exacerbations?